In a direct injection engine, a fuel injection device is mounted on the cylinder head such that the free end of the valve body defining the outer shell of the fuel injection device is exposed in the combustion chamber. Fuel injection orifices are formed at the free end of the valve body, and the fuel is injected into the combustion chamber from the injection orifices according to the movement of a valve member provided in the valve body. It has been proposed to support a pressure detection device at the free end of the valve body in such a fuel injection device to detect the pressure in the cylinder. See Patent Document 1, for instance. According to the fuel injection device disclosed in Patent Document 1, the pressure detection device is provided with an annular configuration so as to receive the free end of the valve body therein, and welded to the valve body so as to be exposed to the combustion chamber.
In such a fuel injection device, because the pressure detection device is supported by the valve body, there is no need to change the configurations of the combustion chamber or the cylinder head for installing the pressure detection device. Because there is no contact between the pressure detection device and the cylinder head, vibrations that could be transmitted to the pressure detection device from sources such as other cylinders, the valve actuating mechanism and the head cover via the cylinder head can be minimized. Also, the pressure detection device is protected from thermal damages owing to the cooling effect of the fuel that passes through the valve body.